Biochar prepared from crop straw is an economical method for adsorbing bromocresol green (BCG) from textile industrial wastewater. However, there is limited research on the adsorption mechanism of biochar for the removal of BCG. This study utilized cucumber straw as raw material to prepare biochar with good adsorption potential and characterized its physicochemical properties. Through adsorption experiments, the effects of solution pH, biochar dosage, and initial dye concentration on adsorption performance were examined. The adsorption mechanism of cucumber straw biochar (CBC) for BCG was elucidated at the molecular level using adsorption kinetics, adsorption isotherm models, and density functional theory (DFT) calculations. Results show that the specific surface area of the CBC is 101.58 m²/g, and it has a high degree of carbonization, similar to the structure of graphite crystals. The presence of aromatic rings, –OH groups, and –COOH groups in CBC provides abundant adsorption sites for BCG. The adsorption process of CBC for BCG is influenced by both physical and chemical adsorption, and can be described by the Langmuir isotherm model, indicating a monolayer adsorption process. The theoretical maximum monolayer adsorption capacity (q_m) of BCG at 298 K was calculated to be 99.18 mg/g. DFT calculations reveal interactions between BCG and CBC involving electrostatic interactions, van der Waals forces, halogen–π interactions, π–π interactions, and hydrogen bonds. Additionally, the interaction of hydrogen bonds between BCG and the –COOH group of biochar is stronger than that between BCG and the –OH group. These findings provide valuable insights into the preparation and application of efficient organic dye adsorbents.

A series of Zr-TiO₂ catalysts were prepared using a facile sol-gel method and were used for N-methylmorpholine (NMM) oxidation to N-methylmorpholine-N-oxide (NMMO). The structure features of Zr-TiO₂ catalysts were studied in detail through a variety of characterization methods, such as XRD, SEM, N₂ adsorption-desorption isotherms, XPS, EPR, and O₂-TPD. As-obtained 5%Zr-TiO₂ catalysts had superior catalytic performance and stability with a 97.6% NMMO yield at 40 °C, which related to Zr doping, a higher surface area, more oxygen vacancies, and oxygen chemisorption on the catalytic surface. This work provides an efficient preparation strategy of TiO₂-based catalysts for selective oxidation reactions by a facile method.

With the advances in engine technology, the exhaust gas temperature of automobiles has further reduced, which in turn leads to an increase in the emissions of carbon monoxide (CO) and hydrocarbons (HCs). In order to understand the influence of CeO₂-based catalysts loaded with different noble metals on the catalytic oxidation activity of CO and HCs, this study constructed catalyst models of Ce_0.875Zr_0.125O₂ (100) surfaces loaded with Pt, Pd, Ag, and Au. The electronic density and state density structures of the catalysts were analyzed, and the reaction energy barriers for CO oxidation and C₃H₆ dehydrogenation oxidation on the catalyst surfaces were also calculated. Furthermore, the activity sequences of the catalysts were explored. The results revealed that after loading Pt, Pd, Ag, and Au atoms onto the catalyst surfaces, these noble metal atoms exhibited strong interactions with the catalyst surfaces, and electron transfer occurred between the noble metal atoms and the catalyst surfaces. Loading with noble metals can enhance the catalytic activity of CO oxidation, but it has little effect on the dehydrogenation oxidation of C₃H₆. Of the different noble metals, loading with Pd exhibits the best catalytic activity for both CO and C₃H₆ oxidation. This study elucidated the influence of noble metal doping on the catalytic activity of catalysts at the molecular level, providing theoretical guidance for the design of a new generation of green and efficient catalysts.

In this work, a tomato biochar composite modified with cetyltrimethylammonium bromide (CTAB@TBC) was successfully synthesized using an ethanol solution method. It was comprehensively characterized to evaluate its morphology (SEM), crystal structure (XRD), chemical bonding (FT-IR and Raman spectroscopy), surface area (BET analysis), and thermal stability (TGA). The adsorption performance of the composite for xylenol orange (XO) was subsequently evaluated in detail. The findings revealed that CTAB@TBC exhibited a maximum adsorption capacity of 150.59 mg/g for XO. Kinetic analysis indicated that the adsorption process conformed to a pseudo-second-order model, implying that chemisorption was the step limiting the rate. The Langmuir model accurately described the adsorption isotherm data, suggesting monolayer adsorption on a uniform surface. Thermodynamic evaluation further revealed a negative Gibbs free energy (ΔG) change, confirming the spontaneity of the adsorption process. In summary, the results suggest that CTAB@TBC is a highly effective adsorbent for eliminating dyes from wastewater and offers considerable promise for treating industrial effluents.

The efficient and effective removal of mixed pollutants from wastewater is of paramount importance for environmental remediation, given the diverse nature of contaminants present. In particular, arsenic (As) and ciprofloxacin (CIP) contamination in surface water has become increasingly severe. To address this challenge, this study synthesizes ZIF-67 and integrates it with the Fenton reaction to remove mixed As(III) and CIP pollutants from wastewater. Comprehensive characterization of ZIF-67 was conducted using FTIR, XRD, SEM, and BET analyses, as well as pHpzc measurements. As an efficient adsorbent, ZIF-67 offers a high surface area (1614 m² g⁻¹) and excels in removing pharmaceutical contaminants. A systematic investigation was conducted to evaluate the influence of key reaction parameters, including pH, H₂O₂/Fe²⁺ ratio, reaction temperature, adsorbent dosage, and reaction time, on pollutant removal efficiency, ultimately determining the optimal reaction conditions. The removal of As(III) and CIP follows a pseudo-second-order kinetic model and fits the Langmuir isotherm. Experimental results demonstrated that the maximum removal efficiencies for As(III) and CIP reached 98.07% and 99.96%, respectively, when ZIF-67 was coupled with the Fenton reaction. Mechanistic studies indicate that during the coupling process, the Fenton reaction generates highly reactive hydroxyl radicals (˙OH). These hydroxyl radicals (˙OH) can oxidize trivalent arsenic and CIP into pentavalent arsenic and intermediate products, which are more easily adsorbed by ZIF-67, thereby enhancing the adsorption efficiency of ZIF-67 for pollutants. By leveraging the synergy of ZIF-67 and the Fenton reaction, this study proposes a promising strategy for enhanced As(III) and CIP removal, offering novel methods for wastewater treatment.